Severing device with controlled triggering

Abstract

Device for severing parts of a concrete work, comprising a container in which an over-pressure is generated by a gas produced by a chemical reaction between a chemical compound and an aqueous solution after a predetermined delay. The container includes the aqueous solution and is attached to a case comprising a first recess for storing the chemical compound. A burst disk is arranged between the first recess and the container for ensuring a total sealing between the chemical compound and the aqueous solution. The case includes a second recess enclosing an electronic trigger, an actuator being controlled by the trigger to cause bursting of the burst disk after a predetermined delay, causing said chemical reaction inside the container.

1. Device for severing parts of a concrete work, comprising a container in which an over-pressure is generated by a gas produced by a chemical reaction between a chemical compound and an aqueous solution after a predetermined delay, the container including the aqueous solution and being attached to a case comprising a first recess for storing the chemical compound, and a burst disk being arranged between the first recess and the container for ensuring a total sealing between the chemical compound and the aqueous solution
 wherein the case includes a second recess enclosing an electronic trigger, an actuator being controlled by the trigger to cause bursting of the burst disk after a predetermined delay, causing said chemical reaction inside the container. 
 
     
     
       2. Device for severing according to  claim 1 , wherein the disk is part of a cap mounted on, and sealing, the case. 
     
     
       3. Device for severing according to  claim 2 , wherein the cap comprises a hole having an internal threading, mating with an external threading on a hub extending the container. 
     
     
       4. Device for severing according to  claim 1 , wherein the actuator of the electronic trigger comprises a pyrotechnical detonator operable by discharge of a capacitor to burst the disk. 
     
     
       5. Device for severing according to  claim 4 , wherein the trigger further comprises a timer circuit operable to control a switching circuit connected in series with the actuator. 
     
     
       6. Device for severing according to  claim 5 , wherein the timer circuit comprises a clock having a quartz crystal time base and a microcontroller. 
     
     
       7. Device for severing according to  claim 4 , wherein the initiation of the delay of the trigger and of the charging of the capacitor is triggered by an arming circuit comprising a magnetic switch cooperating with two permanent magnets of opposed polarities, one of the magnets being stationary and the other being removable through a pin. 
     
     
       8. Device for severing according to  claim 6 , wherein the switching circuit comprises a bipolar transistor having a base connected to an output of the microcontroller through a resistor. 
     
     
       9. Device for severing according to  claim 4 , wherein the detonator is located on a printed circuit board of the trigger or directly on the burst disk. 
     
     
       10. Device for severing according to  claim 1 , wherein the container closed by the cap has a recess limited by two tapered walls forming an acute angle and having a common external outline.